Adjust rack to top position (top and middle positions for 4 servings) and preheat oven to 425 degrees. Wash and dry produce.

Dice potatoes into ½-inch pieces. Cut broccoli into bite-size pieces if necessary. Trim and slice mushrooms into ¼-inch-thick pieces (skip if your mushrooms are pre-sliced!). Roughly chop parsley.

Toss potatoes on one side of a baking sheet with a large drizzle of oil, salt, and pepper. (For 4 servings, spread out across entire sheet.) 

Roast potatoes on top rack for 5 minutes, then remove sheet from oven. Carefully add broccoli to empty side of sheet; toss with a drizzle of oil, salt, and pepper. Return to top rack and roast until broccoli is browned and potatoes are tender and crisped, 15-20 minutes more. (For 4, leave potatoes roasting; add broccoli to a second sheet and roast on middle rack.)

Meanwhile, open package of chicken* and drain off any excess liquid. Season with 1 tsp paprika (2 tsp for 4 servings), salt, and pepper. (You’ll use the rest of the paprika later.)

Heat a drizzle of oil in a large pan over medium-high heat. Add chicken; cook, undisturbed, until browned, 1-2 minutes.

Continue to cook, stirring occasionally, until cooked through, 3-4 minutes more. Turn off heat; transfer chicken to a plate.

While chicken cooks, halve, peel, and finely dice onion.

Melt 1 TBSP butter (2 TBSP for 4 servings) in pan used for chicken over medium-high heat. Add onion; cook, stirring occasionally, until beginning to soften, 1-2 minutes.

Add a drizzle of oil and mushrooms; cook, stirring occasionally, until browned and softened, 3-4 minutes.